With the development of DTV, VOD, Triple-play and FTTx, the information volume of CATV network is increasing rapidly , and bandwidth of 47~862MHz in central station will not be able to satisfy the requirement of single subscriber. In order to provide more interactive service capacity for subscribers, the second-grade service area has to be built in sub-station (second-grade network). In the 1550nm optical system, a 1550nm Narrow-band Multiplexing Optical Transmitter need to be set in the sub-station and FDM (frequency division multiplexing) the local programs and marginal server of sub-station with the main optical signal of the central station. Then it will serve the subscribers in second- grade area through EDFA and optical splitters.

Huatai HT1500WC, HT1500WU are a series of high quality 1550nm Internal Modulated Narrow-band Multiplexing Optical Transmitter. It adopts high linearity, low chirp, cooling DFB laser and builds-in pre-distortion compensation, which improves the system index obviously. Excellent AGC, APC, ATC control, ensure laser's high reliability and long working life. It can be used in second-grade service area (sub-headed) of All-optical 1550nm system, spots local multi-channel analog and digital signal, and provide VOD Value-added services for users.

HT1500WC, HT1500WU have many configurations for the user' s choice. Through these configurations, we can provide concise and reliable links for the users and thus save much space for them.

HT1500WCOO: 1548~1563nm CATV work wavelength, no Wavelength Division Multiplexing (WDM) and variable optical attenuator.

HT1500WCWO: 1548~1563nm CATV work wavelength, built-in WDM, provide main-line input and combined-wave output, laser output power not adjustable.

HT1500WCOT: 1548~1563nm CATV work wavelength, no WDM, single fiber output, built-in variable optical attenuator, TX laser output power adjustable.

HT1500WCWT: 1548~1563nm CATV work wavelength, built-in WDM, provide main-line input and combined-wave output, built-in continuous variable optical attenuator, TX laser output power adjustable.

HT1500WUOO: ITU standard wavelength, ±1.6nm adjustable, no Wavelength Division Multiplexing (WDM) and variable optical attenuator.

HT1500WUWO: ITU standard wavelength, ±1.6nm adjustable, built-in WDM, provide main-line input and combine- wave output, laser output power not adjustable.

HT1500WUOT: ITU standard wavelength, ±1.6nm adjustable, no Wavelength Division Multiplexing (WDM), single fiber output, built-in variable optical attenuator, TX laser output power adjustable.

HT1500WUWT: ITU standard wavelength, ±1.6nm adjustable, built-in WDM, provide main-line input and combined-wave output, built-in continuous variable optical attenuator, TX laser output power adjustable.

 Low chirp, high linearity, cooling DFB laser.

 High efficient laser pre-distortion regulation.

 Perfect laser APC, ATC closed-loop control.

 ITU standard wavelength optional. Users can adjust and enactment the laser wavelength in the front-panel with ±0.05nm stepping within range ±200GHz (±1.6nm). It is suitable for WDM system, as well as network upgrading expanding.

 Build-in WDM optional (with main-line input and combined-wave output), provide concise and reliable links.

 Build-in VOA optional (TX laser output power continuous adjustable), facilitate system modulating.

 1+1 backup power supply optional, switch automatically.

 Build-in fan and forced cooling to ensure the long life span of laser.

 SNMP network management optional and RS232 communication interface.

 Excellent P/P ratio.

It can be used in second-grade service area (sub-headed) of All-optical 1550nm system, spots local multi-channel analog and digital signal with high quality, and provide individuality local program and VOD Value-added services for users.