Abstract: An optical transceiver stores an output A/D value which is A/D-converted from reference voltage in an EEPROM as correction data in preparing the optical transceiver. The optical transceiver, receiving a request for outputting a monitored value from an external device connected therewith, calculates a variation based on difference between the output A/D value which is A/D-converted from the reference voltage at the timing when the request for outputting the monitored value is received and the correction data stored in the EEPROM. Then, the optical transceiver uses the calculated variation to convert current of light-input power which is input thereinto into voltage, amplify the voltage, and A/D-convert the voltage to thereby correct the output A/D value. The optical transceiver outputs the corrected A/D value to the connected external device as the monitored value.

Abstract: An optical receiving apparatus, including an optical interferometer including first and second optical waveguides having light paths different in length and converting a phase modulated signal received by the optical receiving apparatus into an intensity modulated signal, monitors the results of the detecting by the temperature detector and the measuring by the electric current measure while sweeping the temperature of the first optical waveguide in a predetermined range; selects the temperature of the first optical waveguide at which temperature the average photocurrent has an extreme value based on the result of the monitoring; and varies the temperature of the first optical waveguide to the selected temperature.

Abstract: An optical transceiver stores an output A/D value which is A/D-converted from reference voltage in an EEPROM as correction data in preparing the optical transceiver. The optical transceiver, receiving a request for outputting a monitored value from an external device connected therewith, calculates a variation based on difference between the output A/D value which is A/D-converted from the reference voltage at the timing when the request for outputting the monitored value is received and the correction data stored in the EEPROM. Then, the optical transceiver uses the calculated variation to convert current of light-input power which is input thereinto into voltage, amplify the voltage, and A/D-convert the voltage to thereby correct the output A/D value. The optical transceiver outputs the corrected A/D value to the connected external device as the monitored value.

Abstract: An optical switch for switching signal light by allowing the signal light to obliquely enter a non-linear optical thin film 1 containing nano-crystal of metal oxide from a light path disposed in an optical material, and irradiating visible excitation light to the non-linear optical thin film to induce a total reflection phenomenon, thereby controlling the reflection and transmission behavior of the signal light, wherein a difference between a temperature coefficient factor of an optical index of the non-linear optical thin film and that of an optical index of the optical material which is in contact with the non-linear optical thin film is determined to be 15×10?6/° C. or below. Preferably, it is determined to be zero or substantially zero. Thus, an influence due to the temperature increase is cancelled, and a malfunction of switching can be avoided.

Abstract: A light source device has a continous wave (CW) light source for emitting first direct current (DC) light, a level converter for converting optical electric power of the first DC light into second DC light and outputting the second DC light, and a mixer for mixing an optical main signal having a constant extinction ratio with the second DC light.

Abstract: An optical transmitter includes a laser diode drive circuit for driving a laser diode in accordance with a laser diode current that superimposes a pilot signal on a “0” logic level and a “1” logic level of a transmission signal, the pilot signal having a low-frequency compared with the transmission signal, so as to become an opposite phase each other, a monitor circuit for monitoring an optical output of the laser diode, a filter circuit for extracting a low-frequency component of the pilot signal from an output of the monitor circuit, a phase compare circuit for comparing a phase of the low-frequency component of the pilot signal extracted by the filter circuit with a phase of the pilot signal, and a deterioration judgment circuit for judging whether or not the laser diode deteriorates in accordance with a comparison result of the phase compare circuit.

Abstract: An apparatus for controlling an extinction ratio of a light-emitting device, includes: a temperature detecting unit that detects a temperature of the device; a power detecting unit that detects an optical output power of the device; a modulation-current detecting unit that detects a modulation current input into the device; a POW computing unit that computes a power control value for the device based on the temperature; and an ER computing unit that computes an extinction ratio control value for the device based on the power control value, the optical output power, and the modulation current.

Abstract: An optical switch for switching signal light by allowing the signal light to obliquely enter a non-linear optical thin film 1 containing nano-crystal of metal oxide from a light path disposed in an optical material, and irradiating visible excitation light to the non-linear optical thin film to induce a total reflection phenomenon, thereby controlling the reflection and transmission behavior of the signal light, wherein a difference between a temperature coefficient factor of an optical index of the non-linear optical thin film and that of an optical index of the optical material which is in contact with the non-linear optical thin film is determined to be 15×10?6/° C. or below. Preferably, it is determined to be zero or substantially zero. Thus, an influence due to the temperature increase is cancelled, and a malfunction of switching can be avoided.

Abstract: A light source device has a CW light source for emitting first DC light, a level converter for converting optical electric power of the first DC light into second DC light and outputting the second DC light, and a mixer for mixing an optical main signal having a constant extinction ratio with the second DC light.

Abstract: An apparatus of continuous type for producing matured compost-like material comprises: a vertical vessel 1 which is provided at an upper side thereof with an inlet 2 for organic waste and provided at a lower side thereof with an outlet 3 for the material treated with heat; heating panel(s) 4 for heating the material which is disposed within the vessel 1 in multi-stage form or spiral form; and moving means for moving the material within the vessel 1 from the inlet 2 toward the outlet 3. The material within the vessel 1 is heated and dried and is further treated with heat at temperature of 100-200° C., thereby continuously producing compost-like material.