Abstract: A wavelength-tunable light source includes a wavelength-tunable laser including a first region and a second region each of which includes at least one of heaters, a frequency locker configured to receive output light of the wavelength-tunable laser and output two electric control signals whose phases are mutually different by 90° and having frequency period with respect to frequency of the output light, a thermal electric cooler on which the wavelength-tunable laser and the frequency locker are mounted, and a controller configured to control temperature of the heaters, and the thermal electric cooler on the basis of any one of the two electric control signals.

Abstract: A wavelength-tunable light source includes a wavelength-tunable laser including a first region and a second region each of which includes at least one of heaters, a frequency locker configured to receive output light of the wavelength-tunable laser and output two electric control signals whose phases are mutually different by 90° and having frequency period with respect to frequency of the output light, a thermal electric cooler on which the wavelength-tunable laser and the frequency locker are mounted, and a controller configured to control temperature of the heaters, and the thermal electric cooler on the basis of any one of the two electric control signals.

Abstract: An optical signal monitor circuit includes a PD which directly detects an optical signal and converts the optical signal into a photocurrent, and another PD which detects the optical signal and converts the optical signal into a photocurrent. A resistance element converts the photocurrents into voltages for input to an operational amplifier which outputs voltages based on the voltages generated by the resistance element. A switching control circuit switches a connection between the PDs and the resistance element, and a calculation circuit acquires the output of the operational amplifier converted to digital signals such that the switching control circuit controls switching to cause the two photocurrents to flow into the resistance element at individual timings and to cause the two photocurrents to flow into the resistance element at the same timing, and the calculation circuit calculates a corrected digital signal by subtracting with the obtained digital signals.

Abstract: A method to tune an emission wavelength of a wavelength tunable LD is disclosed. The wavelength tunable LD includes two regions each providing micro heaters to modify the refractive index of micro regions provided with power. The method periodically detects a difference between the emission wavelength and the target wavelength. This wavelength difference is converted into power next supplied to respective micro heaters independently.

Abstract: An optical signal monitor circuit is an optical signal monitor circuit including a PD which directly detects an optical signal and converts the optical signal into a photocurrent, a PD which detects the optical signal and converts the optical signal into a photocurrent, a resistance element which converts these photocurrents into voltages, and an operational amplifier which outputs the voltages generated by the resistance element, wherein the optical signal monitor circuit further includes a switching control circuit which switches a connection between the PDs and the resistance element, and a calculation circuit which acquires the output of the operational amplifier as a digital signal, the switching control circuit controls switching to flow the two photocurrents into the resistance element at individual timings and flow the two photocurrents into the resistance element at the same timing, and the calculation circuit calculates a corrected digital signal by subtracting the obtained digital signal.

Abstract: A method to tune an emission wavelength of a wavelength tunable LD is disclosed. The wavelength tunable LD includes two regions each providing micro heaters to modify the refractive index of micro regions provided with power. The method periodically detects a difference between the emission wavelength and the target wavelength. This wavelength difference is converted into power next supplied to respective micro heaters independently.

Abstract: A frame processing system is capable of expanding and contracting a frame having a plurality of frame lines to define a plurality of areas. One of the areas can be expanded or contracted without expanding or contracting the other areas. One of the frame lines is designated by a cursor, for example, and the designated frame line is moved together with the cursor on the display. At this time, all the other frame lines connected to the designated frame line are automatically expanded or contracted to maintain the connection therebetween.

Abstract: In a text editing device, provided is an improved so-called wordout function, a word lying across two lines can be erased at one time with a single key operation. In case that a hyphen is located at the end of the line, it is determined that two divided parts of a single word are located on two lines.By detecting a hyphen between two character strings, these two strings are erased at one time as two parts included in a single word.

Abstract: In a printing device, it is possible to automatically place a print head on the peripheral positions of the print area without actual printing operation.By employing the above arrangement, an operator can exactly determine a proper size of print sheet for the text to be printed, with no waste of sheet and printing time.

Abstract: A word processor having attribute functions such as underline, boldface, superscript, etc., can produce or cancel those attribute effects on the display device by simple operations. The word processor with an attribute mode can either produce the attribute effect which is selected by an attribute key in response to the rightward or downward movement of the cursor, or cancel it in response to the leftward or upward movement. The word processor with an attribute cancel mode in addition to an attribute mode can set a mode among a non-attribute mode, an attribute mode and an attribute cancel mode independent of the direction of the cursor's movement.

Abstract: In a document processing apparatus, the top position of the input data visually displayed on a display unit is displaced toward the end of the line and the corresponding control code mark is represented before the top position of the input data when a control code therefor is input. The apparatus is provided with a shift inhibit for adding space codes in the corresponding area of the input data buffer so that format is not changed despite rewrite of the control code, and a shift permit for displacement of the top position after erasure of said control code mark by the erase signal. Thereby, deformatting is prevented and the document processing is easily carried out.

Abstract: In an input control device for use with an electric typewriter, word processor or computer, provided are a special back key which inputs the command for moving a visual indicator in a direction toward the beginning of a line of data, and a special advance key which inputs the command for moving the indicator in a direction toward the end of the line. With the special back key depressed, the indicator is moved to the beginning of the line when the indicator is within a data string and to the end of data string when the indicator is outside the data string. With the special advance key depressed, the indicator is moved to the end of the data string when the indicator is positioned within the data string except at the end of the data string and to the end of the line when the indicator is outside the data string except at the end of the data string.