TTI TIA-527 User manual

TIA-527
Balanced Optical/Electrical Converter
Terahertz Technologies Inc.169 Clear Road Oriskany NY 13424 [phone] FAX [phone]
E-mail [email protected]
6/2011
Operating Instructions

Introduction..................................................................................................................... 1
Unpacking and Inspection .............................................................................................. 1
Battery Replacement...................................................................................................... 2
Controls .......................................................................................................................... 2
Operating Considerations........................................................................................... 3, 4
Spectral Response ........................................................................................................ .4
Typical Waveforms ........................................................................................................ .5
Specifications ................................................................................................................. 6
Limited Warranty ............................................................................................................ 7
Repair Information.......................................................................................................... 7
Contents

Introduction
The TIA-527 Balanced Optical to Electrical Converter is a convenient battery-operated detector/ampli-
fier combination that mounts directly on the input of an oscilloscope, digitizer, or other readout device.
With a band width of DC to 125 MHz, it accurately provides an electrical replica of the difference of
two optical signals presented to its two matched InGaAs detectors. It is fully capable of driving a 50
ohm cable terminated in its characteristic load.
The TIA-527 has selectable transimpedances of 1.4 KΩand 14 KΩplus a post amplifier with select-
able gains of 1 or 10. Thus the overall responsivity ranges from approximately 1, 000 V/W to 100,
000 V/W at the peak of the detector response curve. Interstage coupling may be switched from DC
to AC to avoid saturation of the second stage in those cases where the signal of interest is combined
with a relatively large DC optical component
Each unit is powered by a self-contained 9 V lithium battery or a universal wall mount power supply.
Battery operation eliminates ground loops and the undesirable effects of conducted radiation that may
be present on local power lines.
Calibration - This is a qualitative measurement device. No calibration is required or necessary.
1
Unpacking and Inspection
Prior to shipment this instrument was inspected and found to be free of mechanical and electrical
defects. Upon acceptance by the carrier he assumes responsibility for its safe arrival. After unpack-
ing, examine the unit for any evidence of shipping damage. Should you receive this instrument in a
damaged condition, apparent or concealed, it must be noted on the freight bill or express receipt and
signed by the carrier’s agent. Failure to do so could result in the carrier refusing to honor the claim.
Upon filing a claim TTI should be notified.

2
Battery Replacement
Each unit comes equipped with a 9 V Lithium battery that provides power to the unit for approximately
30 hours of operation. It is recommended that the battery be replaced whenever the output signal
becomes clipped at 1 volt or less. When replacing the battery,
a Lithium unit should be used. Conventional 9 V alkaline batteries may be used if so desired but the
useful life will only be about 25
% ( 8 hours) of that of the much higher capacity Lithium types. TTI can supply these batteries if de-
sired. Replacement of the battery may be accomplished by removing the four 2-56 Philips flat head
screws that retain the bottom cover of the TIA-527. DO NOT attempt to remove the top cover. Take
care to replace all screws tightly. This will provide optimum shielding of the unit from ambient radio
frequency noise or interference.
The TIA-527 is also supplied with a universal power supply that operates from 90 to 240 VAC, 50-60
Hz. Each unit is equipped with four interchangeable power plugs that equip the unit for use in North
America, Europe, the UK or Australia. Plugging the power supply into the unit disconnects the internal
battery.
Controls
Selects
transimpedance
of first stage
Selects inter-
stage
coupling
Applies power
to the unit
Optical Input
Connectors
Selects gain of
second stage

3
Operating Considerations
The TIA-527 is comprised of two fiber coupled detectors and two amplifier stages. The first ampli-
fier is a transimpedance stage which converts the net detector output current to a voltage by passing
it through a resistor of 1 400 or 14 000 ohms. Additional amplification is optionally provided by the
second stage which also serves to provide 50 ohm drive capability. Either AC or DC coupling between
the stages may be selected.
The overall bandwidth of the unit is determined by the first stage transimpedance. It is in excess of
125 MHz when the T R switch is in the 1.4 K position and is 35 MHz in the 14 K position. The over-
all responsivity of the unit in terms of Volts/Watt is the current responsivity of the detector multiplied
by the transimpedance and further multiplied by the second stage gain. For example, the sensitivity
of the unit at a wavelength of 1300 nm would be 0.7 A/W x 1400 V/A x 10 = 10, 000V/W. It is evident
that the same responsivity may be obtained by using a transimpedance of 14 K and a second stage
gain of one. However, the first setting will provide a bandwidth of 125 MHz while the second will pro-
vide a bandwidth of 35 Mhz. Since the overall peak-to-peak output noise increases with bandwidth,
it it desireable to use the higher transimpedance setting assuming that the signal of interest does not
exceed 35 MHz.
The selection of AC interstage coupling is useful when the user needs to examine a small signal in
the presence of a large DC optical component, (e.g. baseband fiber optic video). This will preclude
the last stage from saturating on the DC component. Otherwise, DC coupling should be employed.
When using the TIA-527 mounted on an oscilloscope, the scope may have its input set to either 50 or
1 Meg ohm input impedance. If driving a coaxial cable, the cable should have a 50 ohm characteristic
impedance and be terminated with a 50 ohm load. Note that the signal amplitude will be reduced by a
factor of two.
The following table summarizes the operation of the unit under various operating conditions.

4
The following table summarizes the operation of the unit under various operating conditions.
Setting
Signal TRAC/DC Coupling 2nd Stage
Small Signal on large DC Components 1.4K AC X1, X10 As Needed
High Frequency signal, >35 MHz 1.4K DC X1, X10 As Needed
Low Level Signal<35 MHz 14K DC X1, X10 As Needed
Low Level, High Frequency Signal 1.4K DC X10
Operating Considerations
continued
Spectral Response
The approximate relative response curves of the detectors employed is as shown below. Note that
these are representative curves and do not necessarily correspond to the exact response of the par-
ticular detector in use.
The approximate power at the detector surface is given by:
Peak output voltage (no load)
0.8 A/W x T Rx % Relative response from graph/100
Peak output voltage (no load)
0.55 A/W x TR x % Relative response from graph/100
Input power in watts (Si) =
Input power in watts (InGaAs) =

5
Typical Waveforms
Optical Input Output; TR= 14 K, Gain = 1
Optical Input Output; TR= 1.4 K, Gain = 10
Optical Input Output; TR= 1.4 K, Gain = 1

6
TTI reserves the right to change specifications without notice.
Specifications
Detector Type Matched InGaAs
Analog Signal Bandwidth (-3 dB) DC to 125 MHz (TR = 1.4 K), DC to 35 MHz (TR = 14 K)
Selectable Trans impedance settings 1.4 K Ohms, 14 K Ohms
Gain Selections X 1 or X 10
Maximum Linear Input Power 1.2 mW
Maximum Input power without damage 10 mW
Spectral Response 850 - 1700 nm
Output Impedance 50 Ohms
Output Connector Male BNC
Fiber Optic Connector FC
Input Numerical Aperture 0.29
Inter-stage Coupling DC or AC (100 Hz Low Frequency Cutoff)
Output Offset Voltage +/- 0.1 Volt
Noise Level 3.6 pW/ root-Hz
Maximum Output Voltage 4 V pk-pk, no load, 2 V pk-pk with 50 Ohm Load
Power Requirements 9 V Battery or supplied universal wall-mount power supply
Battery Life Approximately 30 hours, (no load)
Wall-mount Supply Power Requirements 95-260VAC, 50 - 60 Hz, 16 VA Max.
Mains Connectors Supplied North America, British, Continental Europe, Australian
Dimensions ( mm ) 63 L x 30.5 W x 30 H
Weight 5.6 oz (0.16 Kg)
LED Annunciators Provided Power On
Operating Temperature Range 0 - 40 C
Standard Warranty Two Years, Component and Workmanship, 30 day Satisfaction
Guarantee
Accessories Supplied Transit Case, Universal Power Supply, 9 V ULTRALIFE Lithium
Battery, Manual on CD

7
7
REPAIR INFORMATION
Products manufactured by Terahertz Technologies Inc. are designed and fabricated to provide reliable
performance. However, in the event that service is required, both telephone technical assistance and
factory repair services are available. Call [phone] for information.
For IN-WARRANTY REPAIRS, call us to obtain a Returned Material Authorization number, (RMA
Number). All products are to be returned to TTI with freight charges pre-paid. Those products sent
under warranty will be returned to our customers pre-paid. We cannot be responsible for returned
products that do not reference the TTI RMA number.
For OUT-OF-WARRANTY repairs, services are billable for both time and materials.
Calibration - This is a qualitative measurement device. No calibration is required or necessary.
LIMITED WARRANTY
TERAHERTZ TECHNOLOGIES INC. ( TTI ) WARRANTS THAT TO THE FIRST PURCHASER, FOR A PE-
RIOD OF TWO YEARS FROM THE DATE OF RECEIPT, THAT THIS PRODUCT (THE PRODUCT) WILL BE
FREE FROM DEFECTS IN MATERIALS AND MANUFACTURING. THE FOREGOING WARRANTY IS THE
ONLY WARRANTY, EXPRESS OR IMPLIED, GIVEN BY TTI, I.E., THERE IS NO WARRANTY OF FITNESS
FOR A PARTICULAR PURPOSE. TTI HEREBY DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY
OTHER THAN THE WARRANTY IN THE FIRST SENTENCE TO THE FULLEST EXTENT PERMITTED BY
LAW.
THE SOLE AND EXCLUSIVE REMEDY UNDER THIS WARRANTY IS REPAIR OR REPLACEMENT AT
TTI’S OPTION OF ANY PRODUCT THAT PROVES TO BE DEFECTIVE IN MATERIALS OR MANUFAC-
TURING WITHIN TWO YEARS OF RECEIPT OF THE PRODUCT. NOTE: THIS WARRANTY DOES NOT
APPLY TO ANY PRODUCT WHICH HAS BEEN SUBJECT TO MISHANDLING, MISUSE, OR SERVICE BY
UNAUTHORIZED PERSONNEL OR TO ANY PRODUCT WHICH HAS BEEN DAMAGED, MODIFIED, AL-
TERED OR TAMPERED WITH. TO THE FULLEST EXTENT OF THE LAW, TTI DISCLAIMS ALL LIABILITY
FOR ANY OTHER DIRECT, INCIDENTAL OR CONSEQUENTIAL DAMAGES ALLEGED TO BE CAUSED
BY A DEFECTIVE PRODUCT, I.E., TTI WILL NOT BE RESPONSIBLE FOR ANY PERSONAL INJURY,
PROPERTY DAMAGE OTHER THAN THE COST OF REPLACING THE PRODUCT OR ANY OTHER MON-
ETARY DAMAGE SUCH AS LOST WAGES OR PROFITS CAUSED BY ANY USE, ATTEMPTED USE OR
INABILITY TO USE THE PRODUCT. NOTE: BY USING THE PRODUCT, YOU AGREE THAT REPAIR OR
REPLACEMENT AT TTI’S OPTION WILL FULLY SATISFY TTI’S WARRANTY OBLIGATION TO YOU,
WHETHER IN CONTRACT, TORT, NEGLIGENCE, STRICT LIABILITY OR OTHER APPLICABLE LAW.
Warranty And Repair Information