Newport 2007 Bedienungsanleitung

Model 2007 & 2017 User’s Manual

Nirvana Auto-Balanced

Photoreceivers

Patent No. 5,134,276

These photodetectors are sensitive to electrostatic

discharges and could be permanently damaged if

subjected even to small 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 electrostatic damage

phone: (877) 835-9620

e-mail: tech@newport.com • www.newport.com

Contents

90099912 Rev. A

I Quick Start 3

II Detector Operation 5

III Principles Of Operation 17

IV Operating With Optical Fiber 20

V Applications Examples 22

VI Troubleshooting 30

VII Warranty, Service and Support 32

VIII Specifications 33

This section outlines the quickest path to using the Nirvana

photoreceiver. For more detail on how to operate the Nirvana, see

Section II, Detector Operation. For more information on using the

Nirvana with fiber inputs, see Section IV, Operating With Optical Fiber.

1. Set up your optical experiment with a reference beam impinging on

the REF photodiode and your signal beam impinging on the SIGNAL

photodiode. Use an optical power between 0.1 mW and 1 mW to

facilitate oscilloscope display of your results. Make sure that your

beamsplitter produces more power in the reference beam than in

the signal beam (attenuate the signal beam if necessary).

2. Apply ±15 VDC power to Nirvana. See page 9 for more details on the

power supply connectors.

3. Switch the Linear Output knob to the SIG mode. Turn the Loop

Bandwidth knob to 100. For more detail on this function, see page 14.

4. Attach an oscilloscope to the SIGNAL MONITOR back panel BNC.

Adjust the signal beam coupling, the oscilloscope display control, and

your modulator input settings until the expected voltage waveform

display appears on the oscilloscope. For instance, if your modulator is

an optical chopper running at 1 kHz and 50% duty cycle, your output

oscilloscope trace is expected to be a square wave at 1 kHz, 50% duty

cycle, with an amplitude proportional to the received signal power.

5. Connect the oscilloscope to the back panel LINEAR OUTPUT BNC.

The displayed voltage should again be the expected replica of your

optical modulation. In the case of the chopper input, your displayed

square wave should now show some enhanced edge response.

Quick Start

6. Block the signal beam with an opaque card. Switch the Linear Output

knob to BAL. Adjust the reference beam coupling to maximize the

LINEAR OUTPUT voltage.

7. Unblock both REF and SIGNAL beams and switch the Linear Output

knob to AutoBAL.

8. If you are measuring a DC or low-frequency signal, monitor it on the

LOG OUTPUT. If your signal is at high frequencies, monitor it on the

LINEAR OUTPUT.

The Newport Model 2007 and 2017 Nirvana photoreceivers eliminate

many noise sources that can plague precision measurements. Nirvana’s

wide signal bandwidth and various outputs and settings give you the

flexibility to design inexpensive shot-noise limited experiments with very

little support electronics. Nirvana is designed for use in a dual-beam

setup: one invariant reference path and one signal path which contains

your experiment. Properly applied, Nirvana reduces common mode

noise by over 50 dB at frequencies from DC to 125 kHz. Thus you can

effectively eliminate laser-intensity noise and make shot-noise limited

measurements at low frequencies without using lock-in amplifiers and

optical choppers. Nirvana’s patented circuitry subtracts the reference and

signal photocurrents, canceling noise signals that are common to both

channels. Unlike conventional balanced receivers, Nirvana’s electronic

gain compensation automatically results in balanced detection, even if

the average optical intensities on the two detectors are different and

time-varying. Nirvana’s voltage outputs allow you to measure signal

power with 50 dB less noise than in a single-beam experiment. In most

cases, the noise floor will be determined by shot noise.

Nirvana is easy to use, but we recommend that you read this guide

thoroughly before you try to set up and use the detector. Before using the

photoreceiver in a fiber system, see Section IV, Operating With Optical

Fiber.

Front Panel Controls

The Model 2007 and 2017 photoreceiver inputs consist of two

photodiodes. One is designated the reference photodiode, labeled REF,

while the other is designated the signal photodiode, and labeled SIGNAL.

The outputs of the Nirvana photoreceiver are a set of user-selectable

functions of the optical power applied to these photodiodes. When

planning to use the detector in auto-balanced mode, be sure that the

reference photodiode receives more, and ideally twice as much, optical

power as the signal photodiode.

Note: Since there are no windows on the photodiode, keep the

photodiodes covered when not making measurements for extended

periods of time.

Detector

Operation

REF SIGNAL

SIGNAL

MONITOR

LINEAR

OUTPUT

LOG OUTPUT

±15 VDC

Model 2007

Nirvana Detector

125 kHz (Vis) Auto-Balanced Photorceiver

Loop

Bandwidth

Linear

Output

SIG BAL

AutoBAL

0 100

10 90

20 80

30 70

40 50 60

10X

Nirvana Back Panel

Nirvana TopPanel

Nirvana Front Panel

Top Panel Controls

The function of the Nirvana photoreceiver’s outputs is controlled by a

knob on the top panel. This Linear Output switch controls the operation

of the back panel LINEAR OUTPUT as summarized in the previous table.

With the Linear Output switch set to SIG, the LINEAR OUTPUT BNC

provides a voltage proportional to the signal diode’s photocurrent only.

This function is useful for monitoring the signal power when setting up

the experiment. With the Linear Output switch set to BAL the Nirvana

functions as a traditional balanced detector. The LINEAR OUTPUT BNC

provides a voltage proportional to the difference between the

photocurrents of the signal and reference diodes. Use this mode when

you want a traditional balanced receiver or to verify that the correct ratio

of signal and reference optical powers has been achieved. With the Linear

Output switch set to AutoBAL or 10X, the Nirvana automatically balances

the photocurrents from the signal and reference photodiodes at the

subtraction node. Use these modes for optimum noise cancellation. In

10X mode, the LINEAR OUTPUT BNC’s voltage is ten times greater than

in AutoBAL mode.

Knob Setting Function

SIG Signal monitor, voltage proportional to received SIGNAL optical power.

BAL Traditional balanced detection, voltage proportional to difference

between received SIGNAL and REF optical powers.

AutoBAL Autobalanced detection, zero DC voltage, noise-suppressed AC signal

proportional to received SIGNAL optical power.

10X Autobalanced detection with higher gain. Same as AutoBAL setting,

but with output voltage increased ten times.

Table 1. Back-panel LINEAR OUTPUT BNC function as determined by the top-panel Linear Output

knob position.

The Loop Bandwidth knob controls the cutoff frequency of the electronic

gain compensation in auto-balanced operation. In most experiments, the

optimal setting is 100. Nirvana’s auto-balancing is the result of a low-fre-

quency feedback loop that adjusts the gain of the REF photodiode to

exactly balance the SIGNAL and REF photocurrents. In some cases, it may

be advan-tageous to reduce the bandwidth of this feedback by reducing

the Loop Bandwidth knob setting. For more details on this topic see page

14 and Section III, Principles of Operation.

Back Panel Controls

The back panel of the Nirvana photoreceiver contains the power input

con-nector and three voltage output BNC’s. Power for the Nirvana is

enters through the microconnector power input, labeled ±15 VDC.

The SIGNAL MONITOR BNC directly monitors the optical beam on the

signal photodiode. This voltage output has a transimpedance gain of 10

V/mA for the signal photocurrent. This output is unaffected by the top

panel controls or the REF photodiode optical input so it can be used to

monitor the signal power. The output of the LOG OUTPUT BNC

depends on the top panel Linear Output knob setting. When it is turned

to either AutoBAL or 10X, the LOG OUTPUT voltage is:

otherwise the output voltage is undefined. This output voltage provides a

con-venient measurement of absorption present in the signal path. It is

bandwidth limited, with a bandwidth determined by the Top Panel Loop

Bandwidth knob, and the REF and SIGNAL incident optical powers, as

described in Section III, Principles Of Operation.

LINEAR OUTPUT is a voltage related to the REF and SIGNAL received

optical powers as determined by the top panel Linear Output knob.

LOG OUTPUT P

REF

SIGNAL

~ -1n −











Making A Measurement

Mounting

Nirvana comes with a customer specified English or metric mounting

pad. Insert the mounting pad into the bottom of the detector housing

and secure with the three 4-40 screws provided. The mounting pad has a

tapped 8-32 or M4 thread for convenient mounting to a pedestal or base.

Power Requirements and Cables

Two different power cables are shipped with the photoreceiver: Model

0923 Pico (m8) double-ended, male power cable for use with the

Newport power supply, and a Model 0924 Pico (m8) male to banana plug

power cable for use with other power supplies. If you have a Newport

Model 0901 power supply, use the Model 0923 Pico (m8) double-ended,

male power cable to connect the photoreceiver to one of the power

supply’s 0.3-A microconnector outputs. Use the Model 0924 Pico (m8)

male to banana plug power cable when working with a power supply

other than the Newport Model 0901. Power supply requirements are a

minimum of 0.1 A of current on ±15V. The color convention for the

three banana plugs is:

Banana Plug Voltage Current

Red + 15 V 0.1A

Green COM/GND N/A

Black -15 V 0.1 A

Applying Optical Signals

After mounting the photoreceiver and applying power, direct the signal

and reference beams onto the respective photodetectors. You can check

the cou-pling efficiency of each signal by turning the Linear Output knob

to BAL and monitoring the LINEAR OUTPUT BNC. Successively

blocking each output

with a white card will allow you to optimize the coupling into each

photodetector. When you have optimized the alignment, select your

desired operating mode with the Linear Output knob.

Obtaining 50 dB Noise Suppression

To obtain the best possible noise suppression in autobalanced mode, you

must carefully design your optical experiment. This section of the

manual describes proper selection of parameters such as laser power,

power split ratio, and modulation frequency. Further, it describes several

optical component choices which may affect your perceived noise

performance.

The optical setup can greatly affect the observed noise level in your

measurement. Before beginning your experiment, measure the laser

power, the signal modulation frequency (if any) and the power split ratio

(the ratio of reference to signal power after the beamsplitter). Also

measure (or control) the optical polarization of your beams, and losses in

the signal and reference paths.

Laser Power

Figure 1 shows the common-mode rejection ratio (CMRR) vs. frequency

for different photocurrents. The split ratio was fixed at nearly 2:1.

Notice, the common-mode rejection improves with photocurrent. We

recommend received photocurrents in the mA regime, but a low

frequency CMRR of 50 dB can be obtained at microamp current levels.

Improved high-frequency performance at the lower signal levels can

be obtained through adjustment of the split ratio.

Dieses Handbuch passt für folgende Modelle

Inhaltsverzeichnis

Andere Newport Empfänger Handbücher

Newport

Newport zW Series Bedienungsanleitung

Newport

Newport 2151 Bedienungsanleitung

Newport

Newport NIRVANA Bedienungsanleitung

Newport

Newport 1607-AC Bedienungsanleitung

Newport

Newport 2107 Bedienungsanleitung

Newport

Newport 1807 Bedienungsanleitung

Newport

Newport 1601 Bedienungsanleitung

Newport

Newport 1801 Bedienungsanleitung

Newport

Newport 2051 Bedienungsanleitung

Newport

Newport 1580-A Bedienungsanleitung

Beliebte Empfänger Handbücher anderer Marken

Garmin

Garmin GA 23 Bedienungsanleitung

Aiphone

Aiphone PS-12F Bedienungsanleitung

IMES

IMES TCS-01CA-PMI Bedienungsanleitung

BWI Eagle

BWI Eagle AIR-EAGLE SR Handbuch

AMIMON

AMIMON AMN12310 WHDI Bedienungsanleitung

Dual

Dual DMCPA79BT Betriebsanleitung

Sound Associates

Sound Associates SA652P Bedienungsanleitung

Sherwood

Sherwood NewCastle R-772 Bedienungsanleitung

Audio

Audio A10-RX Series Bedienungsanleitung

AllSee

AllSee PushShare PSRV1.1 Bedienungsanleitung

DEMAG

DEMAG DRC-DR D2 Bedienungsanleitung

Teleco

Teleco TVRCL868A02 Bedienungsanleitung

Bosch

Bosch RF3222E Bedienungsanleitung

Kramer

Kramer 631R Bedienungsanleitung

Xpress

Xpress xmc10 Bedienungsanleitung

JVC

JVC KD-MR1BTS Bedienungsanleitung

Omega Engineering

Omega Engineering UWTC-REC3 Bedienungsanleitung

e-survey

e-survey E300 Pro Bedienungsanleitung