1801 & 1811 User Manual RevG
Contents
1. Model 1801 1811 Wavelength Range 300 1050 nm 900 1700 nm Coupling DC or AC DC or AC 3 dB Bandwidth DC versions DC 125 MHz typical DC 125 MHz typical 3 dB Bandwidth AC versions DC Bias Monitor Bandwidth AC versions only 25 kHz 125 MHz typ DC 50 kHz typical 25 kHz 125 MHz typ DC 50 kHz typical Risetime 3 ns typical 3 ns typical Transimpedance Gain 40 V mA AC 40 V mA AC AC coupled version V mA DC 1 V mA DC Transimpedance Gain 40 V mA 40 V mA DC coupled version Output Impedance 50 500 inimum NEP 3 3 pW Hz 2 5 pW Hz CW Saturation Power 120 uW 950 nm 120 uW 950 nm aximum Pulse Power 5 mW 5 mW Detector Material Type Silicon PIN InGaAs PIN Detector Diameter 0 8 mm 0 3 mm FS 0 1 mm FC Power Requirements 15 V DG 250 mA 15 V DG 250 mA AC coupled units only Optical Input FC or free space FS FC or free space FS RF Output SMA SMA DC Bias Monitor output SMB SMB NEP is frequency dependent See page 9 for more details 12 Characteristics NEW FOCUS Inc Customer Service Technical Support Information and advice about the operation of any New Focus product is available from our applications engineers For quickest response ask for Technical Support and know the model and serial numbers for your product Hours 8 00 5 00 PST Monday through Friday ex2. f Output o y O Transimpedance Compensating Amplifier Difference NZ Amplifier Figure 2 DC Bias Functional KA block diagram of Models1801 l amp 1811 A Transimpedance uc 5 Amplifier AC Versions Optical Input vt V low speed AC Coupled Transimpedance Compensating Amplifier Difference N Amplifier 125 MHz Photoreceivers Operation 9 Figure 3 Responsivity of the photodiode used in the Model 1801 DC Version Figure 4 Responsivity of the photodiode used in the Model 1811 DC Version Figure 5 Typical frequency response top and noise floor bottom At DC the noise floor is 3 3 pW Hz for Model 1801 amp 2 5 pW Hz for Model 1811 10 Operation Responsivity A W Responsivity A W 0 6 10 dB div 1000 1200 1600 1800 160 200 NEW FOCUS Inc Characteristics Physical Specifications Figure 6 lt 300 762 Mechanical drawings of the i w Model 18X1 57 casing i 1 00 25 4 Front View 2 86 72 6 gt E Side View 1 43 36 3 BS Eu Bottom View 125 MHz Photoreceivers Distance from window face to photodetector 1801 2 5mm 1811 0 5mm Back View 8 32 M4 thread DC bias output SMB connector included with AC versions only SMA connector AC coupled output AC version DC coupled output DC version Power connector Characteristics 11 Photodetector Specifications
3. the optical connector is clean and undamaged before connecting it to the detector module Using the Photodetector To obtain optical input 6 Operation 1 Plug one end of the power cable to the connec tor on the back of the module and the other end into a 15 V power supply We recommend the New Focus Model 0901 power supply Turn on the supply Two different power cables have been shipped with your detector a Model 0921 banana plug to microconnector cable and a Model 0922 microconnector to microconnector cable If you have a New Focus Model 0901 power supply use the Model 0922 cable on one of the supply s 0 3 A microconnector outputs Do not use the Model 0921 on the Model 0901 power supply s 0 1 A banana outputs since they do not provide enough current for the receiver Use the Model 0921 cable only with a power supply other than the 0901 NEW FOCUS Inc providing a minimum of 0 25 A of current on 15 V The convention of the three banana plugs is Banana Plug Voltage Red 15V Green COM GND Black 15V 2 Turn on the optical beam 3 For free space beam input align the module so that the beam is incident on the detector surface For fiber optic input connect the fiber optic cable from your optical source to the FC input connector on the front of the module The detector is designed to receive an FC PC connectorized fiber To operate the receiver in the linear region keep the in
4. USER S GUIDE 125 MHz Photoreceivers Models 1801 and 1811 These photodetectors are sensitive to electrostatic discharges and could be permanently damaged if CAUTION subjected to any discharges Ground your self adequately prior to handling these detectors or making connections A ground strap provides the most effective grounding and minimizes the likelihood of demo ah damage NEW FOCUS 5215 Hellyer Ave e San Jose CA 95138 1001 e USA phone 408 284 6808 fax 408 284 4824 e mail contact newfocus com www newfocus com Warranty New Focus Inc guarantees its products to be free of defects for one year from the date of shipment This is in lieu of all other guarantees expressed or implied and does not cover incidental or consequential loss Copyright 2001 New Focus Inc All rights reserved of NEW FOCUS Inc Document Number 180413 Rev G Contents Operation 5 Introductio Law evo Te b an UNE Md OG 5 Handling Precati ones sx 2264 O au ud s adie NN 6 Using the Photodetect t eu GATA 6 NSG eacus hh 8 Characteristics 11 Physical Specifications 5 eorr EE adda A 11 Photodetector Specifications 22222111211 12 Customer Service 13 Technical Support qu ense y ORA A T rA ra DE 13 BEIVICE icz PU ae Sy Dee ios Miia 13 125 MHz Photoreceivers Contents 3 4 Contents NEW FOCUS Inc Operation Introduction The New Focus Models 1801 and 1811 125 MHz low noise photoreceivers addr
5. cluding holidays Toll Free 1 866 NUFOCUS 1 866 683 6287 from the USA amp Canada only Phone 408 284 6808 Support is also available by fax and email Fax 408 980 8883 Email techsupport newfocus com We typically respond to faxes and email within one business day Service In the event that the photoreceiver malfunctions or becomes damaged please contact New Focus for a return authorization number and instructions on shipping the unit back for evaluation and repair 125 MHz Photoreceivers Customer Service 13 14 Customer Service NEW FOCUS Inc
6. ess the needs of the photodetector community in the area of low noise high gain RF photoreception These photoreceivers are available either DC or AC coupled Their typical bandwidth is 125 MHz with a current gain of 40 V mA The performance of these units is achieved through the use of solid RF design together with the implementation of some of the latest advances in commercially available amplifier chips The detector is shielded to avoid RF pickup New Focus offers two models to match your different wavelength needs The specifications at the rear of the manual list each model s characteristics These units address nearly all of the general purpose needs of the RF photoreception community They all have a very large gain bandwidth product low noise high drive capability and a large dynamic range These receivers will enable wide bandwidth low noise detection of signals distributed over fiber optic cables or found in high resolution spectroscopy fiber optic sensors optical metrology and many other applications 125 MHz Photoreceivers Operation 5 Handling Precautions Whenever handling the photoreceiver make sure to follow these precautions Prior to handling the unit or making connections besure to ground yourself adequately even small electrostatic discharges could permanently dam age the device A ground strap provides the most effective grounding and minimizes the likelihood of electrostatic damage Make sure
7. intaining a large bandwidth with flat response This is accomplished by having the gain of the output stage increase with frequency As a result of the increasing gain the noise floor of the receiver increases starting at approx 40 MHz and having a soft peak at approxi mately 110 MHz The equivalent input noise current at the peak is greater than the low frequency noise by a factor of 10 Typical frequency response and noise floor is shown in Figure 5 The transimpedance amplifier in the AC path has an absolute maximum input current of 5 mA and therefore the maximum input optical power is 7 mW Figure 3 and Figure 4 show the responsivity of the photodiodes Power is delivered through a connector on the back of the unit and the entire package is shielded to eliminate RF pickup NEW FOCUS Inc NEP Characteristics For Model 1801 the NEP from 0 10 MHz is 3 3 pW Hz and from 10 200 MHz the NEP is 30 pW Hz Therefore the integrated noise from 0 130 MHz is 328 nW ms and with a conversion gain of 2 4x1 04 VIW the expected output noise voltage is 7 8 mV ms For Model 1811 the NEP from 0 10 MHz is 2 5 pW Hz and from 10 200 MHz the NEP it is 22 5 pW Hz Therefore the integrated noise from 0 130 MHz is 246 nW m and with a conversion gain of 2 4x10 Vl W the expected output noise voltage is 5 9 MV ms Figure 1 V Functional blockdiagram of Models 1801 4 Dts meut amp 1811 DC Versions
8. put power levels well below the cw saturation power specification on page 12 The input power is wavelength dependent and is inversely proportional to the responsivity To set up the output connection 1 Ifyour RF measurement instrument has a male connector connect it directly to the SMA female output connector labeled AC on AC coupled units on the back of the module 2 Ifyour instrument has a female connector con nect with the appropriate cable 3 On AC coupled units monitor the DC bias on the output labeled DC with the provided SMB to BNC cable 125 MHz Photoreceivers Operation 7 Theory 8 Operation The Model 1801 photoreceiver contains a silicon PIN photodiode The Model 1811 contains an InGaAs PIN photodiode In both models the photodiode is fol lowed by a low noise transimpedance amplifier acting asa pre amp with a compensating amplifier as the out put stage A functional block diagram of the DC cou pled version is shown in Figure 1 The AC coupled versions incorporate two extra blocking capacitors a choke and a DC bias monitor circuit The corner frequency of the high pass filter on the AC coupled output is approximately 25 kHz The corner frequency of the low pass filter on the DC bias monitor output is approximately 50 kHz Refer to Figure 2 for a functional block diagram The compensating amplifier allows us to use a large area diode which is intrinsically low speed while ma
Download Pdf Manuals
Related Search