Abstract: A GaAs based semiconductor laser having a combination of cladding layers including a ridge structure part, and a remaining part which overlays the active layers of the laser, and an etch stop layer sandwiched between the ridge structure part and the remaining part. The remaining part preferably overlies the entire surface of laser active layers and has a thickness “D” which satisfies 1.1×W>D?0.5×W wherein W is the width of a spot size having a strength of 1/e2 as measured at the laser front facet in a direction perpendicular to the active layers, wherein “e” is the base of the natural logarithm. The semiconductor laser solves the kink phenomenon to obtain an excellent linear relationship between the optical output power and the injected current.

Abstract: A GaAs based semiconductor laser having a combination of cladding layers including a ridge structure part, and a remaining part which overlays the active layers of the laser, and an etch stop layer sandwiched between the ridge structure part and the remaining part. The remaining part preferably overlies the entire surface of laser active layers and has a thickness “D” which satisfies 1.1×W>D≧0.5×W wherein W is the width of a spot size having a strength of 1/e2 as measured at the laser front facet in a direction perpendicular to the active layers, wherein “e” is the base of the natural logarithm. The semiconductor laser solves the kink phenomenon to obtain an excellent linear relationship between the optical output power and the injected current.

Abstract: A GaAs based semiconductor laser has a combination of cladding layers including a ridge structure part, and a remaining part which overlays the active layers of the laser, and an etch stop layer sandwiched between the ridge structure part and the remaining part. The remaining part preferably overlies the entire surface of laser active layers and has a thickness “D” which satisfies 1.1×W>D≧0.5×W wherein W is the width of a spot size having a strength of {fraction (1/e2)} as measured at the laser front facet in a direction perpendicular to the active layers, wherein “e” is the base of the natural logarithm. The semiconductor laser solves the kink phenomenon to obtain an excellent linear relationship between the optical output power and the injected current.

Abstract: A GaAs based semiconductor laser has a combination of cladding layers including a ridge structure part and a remaining part sandwiching therebetween an etch stop layer. The remaining part overlies the entire surface of laser active layers and has a thickness “D” which satisfies D≧W×0.5 wherein W is the width of a spot size having a strength of 1/e2 for a near field pattern in the active layer in a direction perpendicular to the active layer, wherein “e” is the bottom of the natural logarithm.

Abstract: An optical communication device which has an optical module including an optical element and a lens system optically coupled through a space and housed in a package, a supporting member for supporting the optical module, and a fixing member directly placed over the optical module for removably fixing the optical module on the supporting member, wherein the optical module is securely sandwiched between the supporting member and the fixing member, and a method of fixing the optical module for use in the optical communication device.

Abstract: There is provided a wireless LAN system including a wireless terminal which transmits a frame to and receives a frame from other wireless terminals for connecting wireless channel therebetween, and then transmits data to and receives data from the other wireless terminals through the wireless channel. The other wireless terminals stop transmission on receiving the frame from the wire terminal. The wireless terminal is designed to transmit a frame to and receive a frame from the other wireless terminals at a first data transfer rate for connecting wireless channel therebetween, and thereafter transmit data to and receive data from the other wireless terminals at a second date transfer rate greater than the first data transfer rate. The above-mentioned wireless LAN system ensures that wireless channel connection by means of RTS frame or CTS frame is established at a constant data transfer rate, for instance, at 2.0 Mbps, and data is transferred at a high rate, for instance, at 4.8 Mbps.

Abstract: A GaAs based semiconductor laser has a combination of cladding layers including a ridge structure part, and a remaining part which overlays the active layers of the laser, and an etch stop layer sandwiched between the ridge structure part and the remaining part. The remaining part preferably overlies the entire surface of laser active layers and has a thickness “D” which satisfies 1.1×W>D≧0.5×W wherein W is the width of a spot size having a strength of {fraction (1/e2)} as measured at the laser front facet in a direction perpendicular to the active layers, wherein “e” is the base of the natural logarithm. The semiconductor laser solves the kink phenomenon to obtain an excellent linear relationship between the optical output power and the injected current.

Abstract: An optical communication device which has an optical module including an optical element and a lens system optically coupled through a space and housed in a package, a supporting member for supporting the optical module, and a fixing member directly placed over the optical module for removably fixing the optical module on the supporting member, wherein the optical module is securely sandwiched between the supporting member and the fixing member, and a method of fixing the optical module for use in the optical communication device.

Abstract: In a resistance film tablet system which includes a pair of resistance films superposed on each other and spaced by a predetermined distance therebetween, a value measured at the previous detection is stored in a memory beforehand and is read out for being converted into an analog voltage, then, a capacitance portion of the resistance films is charged with the voltage. The capacitance portion is converged to its convergent value faster, thereby a faster sampling can be operated. It is therefore possible to scan a resistance film tablet system faster by shortening a waiting time after a necessary mode setting, when measuring a voltage at a contact point in X-detection or Y-detection mode.

Abstract: In a semiconductor laser device comprising a semiconductor laser main body having an active layer formed between a pair of cladding layers, and a non-absorbing layer of InGaP formed on the facets of the semiconductor laser main body and having a band gap greater than the band gap of the active layer,a diffusion blocking layer of, for example, Si, SiN or Ge is formed on the surface of the non-absorbing layer, and a di-electric protective layer of, for example, AlO.sub.x, SiO.sub.x, SiN.sub.x or MgO.sub.x for regulating reflectance at the facets and protecting the non-absorbing layer is formed on the diffusion blocking layer.

Abstract: In a battery-powered electronic apparatus having a microprocessor therein, any task is stopped running on the microprocessor in response to a check timing signal and, after the task is stopped running on the microprocessor, an output voltage of the battery is detected. Subsequently, after resuming the task running on the microprocessor, the remaining quantity of the battery is estimated based on the detected output voltage using a discharge characteristic of the battery.

Abstract: A wireless-LAN terminal comprises a wired-LAN controller, a wireless modem and an access controller intervening between the wired-LAN controller and the wireless modem. In the access controller, the termination of data reception and the occurrence of a transmission request are detected by monitoring a frame-sense (FS) signal and a request-to-send (RTS) signal, respectively. An IFS period is generated by a delay timer when the data reception is terminated and a random amount of time is generated by using a backoff algorithm when the transmission request occurs during a transmission inhibition period. The data transmission is waited until the random amount of time comes to an end, and the data transmission is started when the random amount of time has elapsed and the transmission channel is available. Since a backoff period is determined randomly for each terminal, there is a remarkably reduced probability that a plurality of terminals concurrently start the media access for data transmission.

Abstract: A terminal unit for a wireless communication network includes a wireless modem, a wire network controller, and a CPU. The modem can check whether a RTS signal is inputted or not during reception of communication data, and modulates communication data and performs wireless transmission of the data in response to the RTS signal when no communication data is being received, while it temporarily outputs a CTS signal and disables it thereafter in response to the RTS signal when communication data is being received. Upon reception of a data transmission request from the terminal unit, the controller outputs the RTS signal to the modem after completion of reception of communication data when the data is being received, or outputs the RTS signal to the modem when no communication data is being received. The controller determines interruption of data transmission and outputs a RTI signal when the CTS signal from the modem is temporarily input and disabled thereafter.

Abstract: When a wireless network is newly added to one or more existing wireless networks, each of which has a network identifier, it is desirable that a network identifier of the newly added network can be automatically set. The newly added network includes a plurality of terminals. First, network identifiers of the existing networks are received for a predetermined time period and stored in each of the plurality of terminals in a network identifier setting mode. Then, a network identifier of the newly added wireless network is automatically determined based on the stored network identifiers of the existing wireless networks. The determined network identifier is set in each of the plurality of terminals and the terminal mode is switched from the network identifier setting mode to a normal mode in each of the plurality of terminals.