Abstract: A light operation device includes: an light input and output port; an light-operating element reflecting a light input from any one of the ports of the light input and output port and outputting the reflected light to any one of the ports of the light input and output port; a condensing lens system disposed between the light input and output port and the light-operating element and optically-coupling the light input and output port with the light-operating element; an anamorphic optical system disposed between the light input and output port and the condensing lens system and expanding a beam diameter of the light input from a side of the light input and output port in a beam-diameter-expanding direction. In the condensing lens system, a first focal distance in the beam-diameter-expanding direction and a second focal distance in a direction perpendicular to the beam-diameter-expanding direction differ from each other.

Abstract: A light operation device includes: an light input and output port; an light-operating element reflecting a light input from any one of the ports of the light input and output port and outputting the reflected light to any one of the ports of the light input and output port; a condensing lens system disposed between the light input and output port and the light-operating element and optically-coupling the light input and output port with the light-operating element; an anamorphic optical system disposed between the light input and output port and the condensing lens system and expanding a beam diameter of the light input from a side of the light input and output port in a beam-diameter-expanding direction. In the condensing lens system, a first focal distance in the beam-diameter-expanding direction and a second focal distance in a direction perpendicular to the beam-diameter-expanding direction differ from each other.

Abstract: An optical amplifier comprising: a pumping light source supplying a pumping light to an optical fiber as an amplification medium; an ASE light power detector detecting an ASE light power including an external ASE power flowing from an upstream side outside an amplification signal band; and a control unit setting a gain within the amplification signal band by using the ASE light power detected by the ASE light power detector outside the amplification signal band. The control unit controls the pumping light source by compensating for an influence of the external ASE power, obtained by measuring a relationship between the gain within the amplification signal band and the ASE light power outside the amplification signal band, to set initially the gain within the amplification signal band.

Abstract: An optical amplifier comprising: a pumping light source supplying a pumping light to an optical fiber as an amplification medium; an ASE light power detector detecting an ASE light power including an external ASE power flowing from an upstream side outside an amplification signal band; and a control unit setting a gain within the amplification signal band by using the ASE light power detected by the ASE light power detector outside the amplification signal band. The control unit controls the pumping light source by compensating for an influence of the external ASE power, obtained by measuring a relationship between the gain within the amplification signal band and the ASE light power outside the amplification signal band, to set initially the gain within the amplification signal band.

Abstract: An optical switch includes light input/output ports, each having a port group of inputting/outputting a light, an optical path manipulation unit having optical path switching units of switching an optical path of a light from an input port in the port group to an optical path toward an output port in the same port group according to each of the light input/output ports, and a condenser lens condensing light from the light input/output ports on the optical path switching units corresponding to the port groups and optically-couples the light input/output ports with the optical path manipulation unit. The input/output optical paths of the light input/output ports with respect to the condenser lens are parallel to each other between the ports in the same port group and are unparallel to each other between the ports in the different port groups as seen from a direction perpendicular to a port arrangement direction.

Abstract: The present invention provides an optical amplifying apparatus having: a CPU 11 for processing various signals; a plurality of circuits 17, 18 for controlling respective devices 4, 9 required for optical amplification; a first storing unit 14 for storing a program supplied from a user a gate array 12 for storing various parameters for controlling the devices 4, 9, the gate array being updated based on the program which is stored in the first storing unit 14 and sent via the CPU 11; a latch unit 13, provided between the gate array 12 and the circuits 17, 18, for interrupting a signal path from the gate array 12 to the circuits 17, 18 after receiving a starting signal of an update from the CPU 11 until the update being finished and for controlling the circuits 17, 18 based on the parameters stored in the gate array 12 before the signal path is interrupted; and a second storing unit 16 for, at least during the update, storing the various parameters which are stored in the gate array 12 before the update.

Abstract: A proportional constant adjusting circuit is arranged in the AGC circuit of the optical amplifying apparatus, and the proportional constant of the proportional circuit is continuously adjusted in correspondence to the optical input power monitored by the PD and the logarithmic transformation circuit. The AGC circuit controls the pump LD based on the monitored optical input/output power so as to control the gain of the optical amplifier to be a requested value.

Abstract: The present invention provides an optical amplifying apparatus having: a CPU 11 for processing various signals; a plurality of circuits 17, 18 for controlling respective devices 4, 9 required for optical amplification; a first storing unit 14 for storing a program supplied from a user a gate array 12 for storing various parameters for controlling the devices 4, 9, the gate array being updated based on the program which is stored in the first storing unit 14 and sent via the CPU 11; a latch unit 13, provided between the gate array 12 and the circuits 17, 18, for interrupting a signal path from the gate array 12 to the circuits 17, 18 after receiving a starting signal of an update from the CPU 11 until the update being finished and for controlling the circuits 17, 18 based on the parameters stored in the gate array 12 before the signal path is interrupted; and a second storing unit 16 for, at least during the update, storing the various parameters which are stored in the gate array 12 before the update.

Abstract: A proportional constant adjusting circuit is arranged in the AGC circuit of the optical amplifying apparatus, and the proportional constant of the proportional circuit is continuously adjusted in correspondence to the optical input power monitored by the PD and the logarithmic transformation circuit. The AGC circuit controls the pump LD based on the monitored optical input/output power so as to control the gain of the optical amplifier to be a requested value.

Abstract: A proportional constant adjusting circuit is arranged in the AGC circuit of the optical amplifying apparatus, and the proportional constant of the proportional circuit is continuously adjusted in correspondence to the optical input power monitored by the PD and the logarithmic transformation circuit. The AGC circuit controls the pump LD based on the monitored optical input/output power so as to control the gain of the optical amplifier to be a requested value.

Abstract: A proportional constant adjusting circuit is arranged in the AGC circuit of the optical amplifying apparatus, and the proportional constant of the proportional circuit is continuously adjusted in correspondence to the optical input power monitored by the PD and the logarithmic transformation circuit. The AGC circuit controls the pump LD based on the monitored optical input/output power so as to control the gain of the optical amplifier to be a requested value.

Abstract: An optical amplification apparatus estimates a gain deviation over a range of multiplex wavelength of a signal light received from an EDFA in the preceding stage, selects a gain profile, with which the gain deviation becomes a minimum, from a gain profile storage section, and determines the gain profile. This optical amplification apparatus further controls an HPU (High power pumping light source) according to the determined gain profile and performs Raman amplification on the received signal light.

Abstract: The present invention provides a wavelength division multiplex light communication system using an optical amplifier which can amplifying and translating a multiplex light signal obtained by wavelength division multiplexing a plurality of channel light signals and can perform its control such that when the number of channels n is the maximum number of channels nmax, the total light output power Pt is maximum, Pmax and such that when the number of channels n for light signals is smaller than nmax, the total light output power Pt obtained by amplifying said multiplex light signal is substantially Pt>Pmax×n/nmax.

Abstract: An optical amplification apparatus estimates a gain deviation over a range of multiplex wavelength of a signal light received from an EDFA in the preceding stage, selects a gain profile, with which the gain deviation becomes a minimum, from a gain profile storage section, and determines the gain profile. This optical amplification apparatus further controls an HPU (High power pumping light source) according to the determined gain profile and performs Raman amplification on the received signal light.

Abstract: Rare earth element doped silica glass according to the invention is prepared by doping silica-based glass co-doped with a rare earth element and aluminum additionally with fluorine and has excellent physical properties including remarkable light emission characteristics and an excellent capability of being fused with other silica-based glass. Such doped silica glass provides high amplification gains and a wide wavelength bandwidth and therefore can be used as a material for manufacturing miniaturized optical devices. Particularly, since the manufacturing process adapted to produce rare earth element doped silica glass according to the invention does not involve crystallization that normally characterizes the type of doped silica glass under consideration, the obtained doped silica glass is transparent and totally free from air bubbles.