MKS Newport 1801 User manual

125 MHz PHOTORECEIVERS
MODELS 1801 AND 1811
User‘s Manual
PART 90099905. REV B- 6/28/23
FAX: [phone]
E-MAIL: [e-mail]
WWW.NEWPORT.COM
1791 DEERE AVENUE
IRVINE, CA 92606
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PART 90099905. REV B-6/28/23
USER‘S MANUAL
Copyright © 2023 by MKS Instruments, Inc.
All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means,
electronic or mechanical, including photocopying and recording, or by any information storage or
retrieval system, except as may be expressly permitted in writing by MKS Instruments, Inc.
mksinst™is a trademark of MKS Instruments, Inc.
The New Focus logo and symbol are registered trademarks of MKS Instruments, Inc.

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USER‘S MANUAL
Table of Contents
List of Figures and Tables .........................................................................................................................4
1Warranty ...............................................................................................................................................5
1.1 Limitation of Warranty .................................................................................................................5
2Safety Information ................................................................................................................................6
2.1 Safety Procedures and Precautions ...........................................................................................6
2.2 Symbols Used in This Instruction Manual...................................................................................6
3Operation ..............................................................................................................................................7
3.1 Introduction..................................................................................................................................7
3.2 Handling Precautions ..................................................................................................................8
3.3 Using the Photodetector..............................................................................................................8
3.4 Theory .........................................................................................................................................9
4Characteristics....................................................................................................................................14
4.1 Physical Specifications..............................................................................................................14
4.2 Photodetector Specifications.....................................................................................................15
5Customer Service ...............................................................................................................................16
5.1 Technical Support .....................................................................................................................16
5.2 Service ......................................................................................................................................16

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List of Figures and Tables
Figure 1: Functional block diagram of Models 1801 & 1811 (DC versions). ...........................................10
Figure 2: Functional block diagram of Models 1801 & 1811 (AC versions). ...........................................10
Figure 3: Responsivity of the photodiode used in the Model 1801 (DC version). ...................................11
Figure 4: Responsivity of the photodiode used in the Model 1811 (DC version). ...................................11
Figure 5: Typical frequency response .....................................................................................................12
Figure 6: Typical input referred noise of the 18x1 products ....................................................................12
Figure 7: Typical output noise of the 18x1 products................................................................................13
Table 1. 1801 and 1811 series specifications. ........................................................................................15

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USER‘S MANUAL
1 Warranty
Newport Corporation warrants that this product will be free from defects in material and workmanship
and will comply with Newport’s published specifications at the time of sale for a period of one year from
date of shipment. If found to be defective during the warranty period, the product will either be repaired
or replaced at Newport's option. To exercise this warranty, write or call your local Newport office or
representative, or contact Newport headquarters in Irvine, California. You will be given prompt
assistance and return instructions. Send the product, freight prepaid, to the indicated service facility.
Repairs will be made and the instrument returned freight prepaid. Repaired products are warranted for
the remainder of the original warranty period or 90 days, whichever first occurs.
1.1 Limitation of Warranty
The above warranties do not apply to products which have been repaired or modified without Newport’s
written approval, or products subjected to unusual physical, thermal or electrical stress, improper
installation, misuse, abuse, accident or negligence in use, storage, transportation or handling. This
warranty also does not apply to fuses, batteries, or damage from battery leakage. THIS WARRANTY IS
IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING ANY IMPLIED
WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. NEWPORT
CORPORATION SHALL NOT BE LIABLE FOR ANY INDIRECT, SPECIAL, OR CONSEQUENTIAL
DAMAGES RESULTING FROM THE PURCHASE OR USE OF ITS PRODUCTS.
CAUTION These photodetectors and photoreceivers are sensitive to electrostatic
discharges and could be permanently damaged if subjected to any
discharges. Ground yourself adequately prior to handling these
detectors or making connections. A ground strip provides the most
effective grounding and minimizes the likelihood of electrostatic
damage.
This manual has been provided for information only and product specifications are subject to change
without notice. Any change will be reflected in future printings.

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USER‘S MANUAL
2 Safety Information
2.1 Safety Procedures and Precautions
The following general safety precautions must be observed during all phases of operation of this
instrument. Failure to comply with these precautions or with specific warnings elsewhere in this manual
violates safety standards of intended use of the instrument and may impair the protection provided by
the equipment. MKS Instruments, Inc. assumes no liability for the customer’s failure to comply with
these requirements.
DO NOT SUBSTITUTE PARTS OR MODIFY INSTRUMENT
Do not install substitute parts or perform any unauthorized modification to the instrument. Return the
instrument to an MKS Calibration and Service Center for service and repair to ensure that all safety
features are maintained.
SERVICE BY QUALIFIED PERSONNEL ONLY
Operating personnel must not remove instrument covers. Component replacement and internal
adjustments must be made by qualified service personnel only.
2.2 Symbols Used in This Instruction Manual
Definitions of, NOTE, CAUTION, WARNING and DANGER messages used throughout the manual.
NOTE The NOTE sign denotes important information. It calls attention to a
procedure, ractice, condition, or the like, which is essential to highlight.
CAUTION The CAUTION sign denotes a hazard. It calls attention to an operating
procedure, practice, or the like, which, if not correctly performed or
adhered to, could result in damage to or destruction of all or part of the
product.
WARNING The WARNING sign denotes a hazard. It calls attention to a
procedure,practice, condition, on the like, which, if not correctly
performed or adhered to, could result in injury to personnel.
DANGER The DANGER sign Indicates an imminently hazardous situation that, if
not avoided, will result in death or serious injury.

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3 Operation
3.1 Introduction
The Newport Models 1801 and 1811 125-MHz, low noise photoreceivers address 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
ease shielded to avoid RF pickup. Newport offers two models to match your different wavelength
needs. The specifications at the rear of the manual list each model's characteristics.
These units addressed nearly all of the general purpose needs of the RF photo reception community.
They all have a very large gain-bandwidth product, low noise, high drive capability and a large dynamic
range. These receivers will enable enable wide bandwidth lower noise detection of signals distributed
over fiber optic cables or found in high resolution spectroscopy, fiber optic sensors, optical metrology,
and many other applications.
CAUTION Only qualified individuals should perform the installation and any
adjustments. They must complywith all the necessary ESD and
handling precautions while installing and adjusting the instrument.
Proper handling is essential when working with all highly sensitive
precision electronic instruments.
NOTE Do not discard any packing materials unless you have completed your
inspection and are sure he unit arrived safely.

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3.2 Handling Precautions
Whenever handling the photo receiver, make sure to follow these precautions:
•Prior to handling the unit or making connections, be sure to ground yourself adequately-even
small electrostatic discharges could permanently damage the device. A ground strap provides
the most effective grounding and minimizes the likelihood of electrostatic damage.
•Make sure the optical connector is clean and undamaged before connecting it to the detector
module.
3.3 Using the Photodetector
To obtain optical input:
1. Plug one end of the power cable to the connector on the back of the module and the other end
into a ±15 Volt power supply. Turn on the supply. Two different power cables have been
shipped with your detector: a model 0924 banana plug to Pico (m8) cable and a Model 0923
Pico (m8) to Pico (m8) cable. The convention of the three banana plugs is:
Banana Plug
Voltage
Red
+15 V
Green
COM/GND
Black
-15 V
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 set up the output connection:
1. if your RF measurement instrument has a male connector, connected directly to the SMA
female output connector (labeled “AC” on AC-couple units) on the back of the module.
NOTE to operate the receiver in the linear region, keep the input power levels
well below The CW saturation power specification on page 12 period
(the input power is wavelength dependent and is inversely proportional
to the responsivity.)

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2. If your instrument has a female connector, connect 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.
3.4 Theory
The Model 1801 photoreceiver contains a silicon/PIN photodiode. The Model 1811 contains an
InGaAs/PIN photodiode. In both models, the photodiode is followed by a low-noise transimpedance
amplifer. A functional block diagram of the DC-coupled version is shown in Figure 1.
The AC-coupled versions incorporate blocking capacitors 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.
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.
The 3-dB bandwidth is typically in excess of 125 MHz for the Model 18x1 photoreceivers. See the
typical frequency response plot in Figure 5.
The output noise for the 18x1 family is 5 mVrms when measured on a >250-MHz, 50-ohm oscill-
oscope. For additional information on 18x1 noise performance, see the typical Input Referred Noise
and typical Output Noise plots in Figure 6 and 7.

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Figure 2: Functional block diagram of Models 1801 & 1811 (AC versions).
Figure 1: Functional block diagram of Models 1801 & 1811 (DC versions).