Olson Technology OT-1000-HH Rev.X4 - Manual (Page 8)

025-000573 Rev. X4 - 8 - www.olsontech.com
The transmitter offers two RF inputs, allowing easy combining of broadcast (BC) and narrowcast (NC) sig-
nals:
• A low level RF signal input, generally dedicated to broadcast signals in downstream applications, and
• A high-level RF signal input, generally dedicated to narrowcast signals in downstream applications. The
high-level input requires a 14 dB higher RF input level in order to obtain the same OMI (optical modu-
lation index) as on the low-level input.
Test point TP1 is the output of a directional coupler, allowing the operator to measure and supervise the com-
bined RF input signal available with a level of -20dB related to the “low” input or -6dB related to the “high”
input.
Additionally a laser driver test point (TP2) is available, allowing the user to measure:
• The optical output power of the transmitter simply by measuring a DC voltage, which is proportional to
the actual optical DC power in mW. (0.1Volts = 1mW)
• The optical modulation index (OMI), by measuring the RF level at the test-point. An RF level of
+20dBmV corresponds to 5% (peak) optical modulation index at nominal optical output power.
A general-purpose amplifier including laser pre-distortion and laser pre-chirping technology follows the di-
rectional coupler. This amplifier features:
• Variable gain adjustment
• Variable slope adjustment
The microprocessor (µP) uses the detected RF signal at the laser to establish an automatic load control (ALC)
of the laser driver, thus preventing under- or over-modulation of the laser.
The cooled laser versions are equipped with a thermoelectric cooler in on order to achieve a stable transmis-
sion and wavelength performance.
The OT-1000-HH offers the possibility to fine-tune the optical wavelength of the laser optical frequency by
±100GHz in steps of 50GHz for DWDM operation. Additionally the OT-1000-HH transmitter supports SBS
suppression technology for a SBS threshold of up to +15dBm. Laser pre-chirping technology is implemented
to optimize the transmission performance for a distinct transmission distance. An electronic compensation
circuitry reduces the impact of dispersion on the transmission performance especially regarding CSO.