A high speed satellite-based laser communications system and method for communications between a satellite-based transmitter system and a ground-based receiver over a free space optical link. The satellite-based transmitter system includes an encoder to encode data, a polarization modulator to linearly polarize the encoded data, one or at least two transmitters to transmit the laser beam, and a quarter-wave optical wave plate to circularly polarize the signal to be transmitted. The ground-based receiver includes an automatic gain control to apply AGC to the received data before the polarizations are reversed and the data is decoded. The system enables an increased data throughput and reduces or eliminates the effects of signal fading.

Example fiber amplifiers and gain adjustment methods for the fiber amplifiers are described. One example fiber amplifier includes a first power amplifier, a wavelength level adjuster, and a controller, where the first power amplifier is connected to the wavelength level adjuster. The controller includes a first input end and a control output end. The first input end is configured to receive an input optical signal, and the control output end is configured to output a first amplification control signal to the first power amplifier, and output an adjustment control signal to the wavelength level adjuster. The wavelength level adjuster is configured to perform power adjustment on each wavelength in a separate manner based on the adjustment control signal.

In order to solve the problem that the power consumption of optical amplifiers is not optimized over the life time of a network whose capacity in use varies, an optical amplifier according to an exemplary aspect of the invention includes a gain medium for amplifying a plurality of optical channels, the gain medium including a plurality of cores through which the plurality of optical channels to propagate respectively and a cladding area surrounding the plurality of cores; monitoring means for monitoring the plurality of optical channels inputted into the gain medium and producing a monitoring result; a first light source configured to emit a first light beam to excite the cladding area; a second light source configured to emit a plurality of second light beams to excite each of the plurality of cores individually; and controlling means for making a decision as to whether each of the plurality of cores to transmit one of the plurality of optical channels based on the monitoring result, and controlling the first light source and the second light source based on the decision.

In order to solve the problem that the power consumption of optical amplifiers is not optimized over the life time of a network whose capacity in use varies, an optical amplifier according to an exemplary aspect of the invention includes a gain medium for amplifying a plurality of optical channels, the gain medium including a plurality of cores through which the plurality of optical channels to propagate respectively and a cladding area surrounding the plurality of cores; monitoring means for monitoring the plurality of optical channels inputted into the gain medium and producing a monitoring result; a first light source configured to emit a first light beam to excite the cladding area; a second light source configured to emit a plurality of second light beams to excite each of the plurality of cores individually; and controlling means for making a decision as to whether each of the plurality of cores to transmit one of the plurality of optical channels based on the monitoring result, and controlling the first light source and the second light source based on the decision.

An optical transmission device includes a reception unit that receives a first signal light and a second signal light, the first and second lights having power levels that respectively correspond to transmission distances and being transmitted; an amplification unit that amplifies the first signal light and the second signal light in accordance with a signal light having a high power level from among the received first signal light and second signal light; and a transmission unit that performs transmission of the amplified first signal light and second signal light.

In order to realize a variable equalizer which is compact and has a wide range of tilt level adjustment, this variable equalizer is provided with a first optical equalizer group including a plurality of first equalizers having mutually different tilt amounts, a second optical equalizer group including a plurality of second equalizers, and an optical element for forming the optical path of an optical signal so that an inputted optical signal is outputted passing through a selected first optical equalizer and a selected second optical equalizer, at least one of the plurality of second optical equalizers having a tilt amount different from any of the plurality of first optical equalizers.

Apparatus for providing communication between ground-based User Equipment (UE) and at least one core network and a method for providing wireless communication between ground-based User Equipment (UE) and at least one core network are disclosed. The apparatus for providing communication between ground-based User Equipment (UE) and at least one core network comprises a plurality of low earth orbit satellites each comprising at least one satellite-based optical transmitter element and at least one satellite-based optical receiver element for providing at least one optical communication link; and at least one aerial vehicle comprising at least one aerial vehicle based optical transmitter element and at least one aerial vehicle based optical receiver element for providing at least one optical communication link and at least one directional antenna for providing a wireless communication link to a ground-based station and/or mobile UE.

Apparatus for providing communication between ground-based User Equipment (UE) and at least one core network and a method for providing wireless communication between ground-based User Equipment (UE) and at least one core network are disclosed. The apparatus for providing communication between ground-based User Equipment (UE) and at least one core network comprises a plurality of low earth orbit satellites each comprising at least one satellite-based optical transmitter element and at least one satellite-based optical receiver element for providing at least one optical communication link; and at least one aerial vehicle comprising at least one aerial vehicle based optical transmitter element and at least one aerial vehicle based optical receiver element for providing at least one optical communication link and at least one directional antenna for providing a wireless communication link to a ground-based station and/or mobile UE.

An optical transmission apparatus includes an amplifier array device; and a switch device coupled to the amplifier array device via an optical cable, wherein the amplifier array device includes a plurality of amplifiers configured to amplify a plurality of optical signals at mutually different wavelengths and to output the plurality of amplified optical signals, a plurality of beam separators configured to generate a plurality of separated light beams by separating the plurality of amplified optical signals and to output the plurality of separated light beams, a beam combiner configured to generate combined light by combining the plurality of separated light beams and to output the combined light to the switch device through the optical cable, and a photo-detector configured to detect a power of the combined light returned from the switch device through the optical cable.

An optical transmission apparatus includes an amplifier array device; and a switch device coupled to the amplifier array device via an optical cable, wherein the amplifier array device includes a plurality of amplifiers configured to amplify a plurality of optical signals at mutually different wavelengths and to output the plurality of amplified optical signals, a plurality of beam separators configured to generate a plurality of separated light beams by separating the plurality of amplified optical signals and to output the plurality of separated light beams, a beam combiner configured to generate combined light by combining the plurality of separated light beams and to output the combined light to the switch device through the optical cable, and a photo-detector configured to detect a power of the combined light returned from the switch device through the optical cable.