THORLABS EDFA300S and EDFA300P C-Band Erbium-Doped Fiber Amplifiers Instruction Manual

EDFA300S and EDFA300P C-Band Erbium-Doped Fiber Amplifiers
Instruction Manual

EDFA300S and EDFA300P
C-Band Erbium-Doped
Fiber Amplifiers
Operating Manual

Chapter 1 Warning Symbol Definitions

Note: Throughout this manual, references to temperature are with respect to °C.
Below is a list of warning symbols you may encounter in this manual or on your device.

Chapter 2 Safety

All statements regarding safety of operation and technical data in this instruction manual will only apply when the unit is operated correctly.

SHOCK WARNING
High voltage inside. To avoid electrical shock, before powering the unit on, make sure that the protective conductor of the 3-conductor power cord is correctly connected to the protective earth contact of the socket outlet. Improper grounding can cause electric shock resulting in severe injury or even death. Do not operate without cover installed.
EXPLOSION WARNING
This instrument must not be operated in an explosion endangered environment.
LASER WARNING
Avoid Exposure – Radiation Emitted from apertures. Do not look into the laser aperture while the laser is on. Injury to the eye may result. Laser should not be turned on unless there is an optical fiber connected to the laser output port. Caution – Use of controls or adjustments or performance of procedures other than those specified herein may result in hazardous radiation exposure.
CAUTION
Note: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed to  provide reasonable  protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and receiver.
• Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
• Consult the dealer or an experienced radio/TV technician for help.

CAUTION
This instrument should be kept clear of environments where liquid spills or condensing moisture are likely. It is not water resistant. To avoid damage to the instrument, do not expose it to spray, liquids, or solvents.
The unit is supplied with a region-specific power cord. If using your own power cord, make sure it is IEC 320 compatible.
Make sure that the line voltage rating marked on the rear panel agrees with your local supply and that the appropriate fuses are installed. Changing of the mains fuse can be done by the user (see Section 4.2, Changing the Fuse). With the exception of the mains fuses, there are no user serviceable parts in this product.
Do not operate in wet or damp conditions. Do not obstruct the air ventilation slots in the housing!
This device can only be returned when packed into the complete original packaging, including all foam packing inserts. If necessary, ask for a replacement package.
Mobile telephones, cellular phones, or other radio transmitters should not to be used within the range of three meters of this unit since the electromagnetic field intensity may exceed the maximum allowed disturbance values according to EN50082-1.

Chapter 3 Description

Thorlabs’ EDFA300S and EDFA300P are core-pumped Erbium-doped fiber amplifiers that provide >40 dB small signal gain and >300 mW saturated output power. The amplifiers are offered in a compact, turnkey benchtop package with FC/APC input and output connectors and in two single-mode (SM) and polarization- maintaining (PM) models. The EDFA300S SM (non-PM) amplifier is polarization- insensitive and input/output fibers to the amplifier are standard single-mode fiber (SMF-28 Ultra). The EDFA300P PM amplifier is polarization sensitive, only amplifying light that is linearly polarized along the slow axis. The input and output fibers of the PM amplifier are polarization maintaining fiber (PM1550-XP) and the connector keys are aligned the slow axis of the fibers. The EDFAs include precision current drivers to adjust the pump laser power in the amplifier. The current adjustment, done through an adjustment knob on the front panel, varies the amplifier gain. The amplifier includes input and output isolators to protect the input laser source from any amplified spontaneous emission or back reflections, as well as to prevent the pump light from exiting the amplifier.
The EDFA gain can be controlled in constant current control (ACC) mode via the front panel interface. The pump current of the amplifier is adjustable through the instrument’s front panel, allowing the user to vary the gain and output power. The display screen shows the pump level, as well as the temperature and emission status. An indicator light is also included on the enable button to show when the internal laser is active. In addition to this mode of operation, the EDFA can be operated in constant power control (APC) and constant gain control (AGC) modes using a command-line interface via USB connection with a PC. These modes of operation allow the user to control the amplifier for a fixed output power level or a fixed gain value. The amplifier automatically adjusts the pump current in order to maintain the power or gain target values. For further information regarding all three modes of operation, please see Chapter 5.
For added safety, there is an interlock connector located on the rear panel that must be shorted in order for the output to be enabled. This can easily be configured to be triggered by doors to disable the fiber amplifier in unsafe conditions. An enable button must be set to activate the amplifier, and a green LED indicator displays the current state of the unit. There is a 3 second delay before the fiber amplifier turns on, and the user is warned by the rapidly blinking LED.
The amplifier includes a universal power supply allowing operation over 100 to 240 VAC without the need for selecting the line voltage. The fuse access is conveniently located on the rear panel.
3.1. Shipping List
The EDFA300 units consist of the following components:

• C-Band Erbium-Doped Fiber Amplifier in Benchtop Package
• Interlock-Shorting BNC Connector
• Region-Specific Power Cord
• FBC250 Connector and Bulkhead Cleaner
• 1 m long FC/APC patch cables (P3-SMF28Y-FC-1 or P3-SMF28E-FC-1 for SM, P3-1550PMY-1 or P31550PM-FC-1 for PM); please see section 4.4 for how to safely connect  to the amplifier ports and minimize the risk of connector damage.
• Sacrificial fiber interface for connection to the output port (please see section 4.4).

Chapter 4 Setup

CAUTION
Prior to using the EDFA systems, it is highly recommended to clean the input and output bulkheads as well as the connector facets to be connected to the bulkheads. Failure to clean the connectors can result in damage to the internal connectors in the EDFA as well as the connectors on fiber patch cables connected to the amplifier.
Please follow one of the two recommended methods to connect the output of the amplifier to the optical setup. Failure to use one of these methods can significantly increase the risk of damaging the output connector of the amplifier.
When cleaning the connectors, ensure that the EDFA is powered off by turning off the push-button switch. Never inspect optical connectors unless all light sources in your setup have been switched off. Please refer to Section 9.2 for further instructions regarding connector cleaning.
4.1. Setting the AC Line Voltage
The fiber amplifier has been shipped configured for 100 to 240 VAC operation. There is no end user adjustment of the line voltage for 110 or 220 VAC. The user needs to select the correct AC cord for their location.
4.2. Changing the Fuse
To change the power fuse, follow the following steps.

1. Remove the AC power cord if it is connected to the unit.
2. Locate the fuse tray directly adjacent to the AC power cord connection on the rear panel of the unit.
3. Carefully use a flat blade screwdriver to open the fuse tray.
4. Remove the existing fuses and install two fuses with the appropriate specifications. The replacement fuses must be 5 mm x 20 mm, 2 A, 250 VAC, slow-blow type.
5. Push the fuse tray back into place making sure that it snaps and sits correctly.
6. Connect the appropriate power cord into the AC receptacle and plug the unit in.

4.3. Initial Setup

1. Set the unit on a dry, level working surface.
2. Plug the female end of the provided AC line cord into the IEC input receptacle on the rear of the unit. Plug the male end into a properly grounded AC socket.
3. Install the interlock BNC connector. (See Chapter 7 for details on the interlock circuitry.)

4.4. Making Fiber Connections to the Amplifier

1. Input Connection: Connect the input to be amplified to the input fiber receptacle using a FC/APC fiber patch cable, carefully cleaning both the input FC bulkhead connector and the patch cable connector beforehand.
2. Output Connection: It is highly recommended to minimize the number of times that a cable is connected to the output receptacle in order to reduce the probability of damage to this connector. Repeated connection to this port can cause a build-up of contamination on the internal connector surface, which can damage the connector at high powers. There are two components shipped with every amplifier for this purpose:
   a. A one meter FC/APC patch cable is included. The connectors on this cable have been pre-cleaned and are ready to mate with the output of the amplifier. Please inspect one end of this cable for any contamination, and connect one end of the cable to the amplifier. Keep this end connected at all times, while using the other end to make connections to the optical setup. This end should still be regularly inspected and cleaned when needed. This approach protects the output receptacle on the amplifier from repeated connections and the resulting optical damage. In the event that the cable end is damaged due to over-usage, it can be replaced with a new cable or a new fiber pigtail can be spliced.
   b. A sacrificial optical interface compatible with FC/APC connectors is supplied with the amplifier. This interface can be plugged into the output port of the amplifier. All fiber cable connections can be made to this interface while the interface should stay connected to the output port. This option will introduce approximately 0.7 dB of extra insertion loss, but it offers the advantage of preventing direct contact between a fiber cable and the internal connector surface to reduce the risk of damage to the internal connector. Additionally, using this method shortens the fiber path outside the amplifier for applications that are sensitive to the fiber length.

Important Note: Please note that when the amplifier is enabled, it generates amplified spontaneous emission (ASE) even when there is no input light entering the amplifier. This should be considered when connecting measurement instruments to the output port of the amplifier and when inspecting the fiber connectors.

Chapter 5 Operation

5.1. Front and Back Panel Overview Figure 1 Front and Rear Panels of the Fiber Amplifier (EDFA300S or EDFA300P)
5.2. Turning On the Amplifier

1. Please consult with your organization’s laser safety officer regarding proper operation of the amplifier at your institution.
   LASER WARNING
   The amplifier generates invisible amplified spontaneous emission (ASE) even without any optical input. The power level of the ASE can be as high as 200 mW. Therefore, all laser safety measures should be followed even if the input light to the amplifier has been disconnected or switched off.
   Additionally, it should be noted that connecting a laser to the output port of the amplifier by mistake can cause damage to the laser due to the ASE light getting coupled into the laser source.

2. Turn on the AC power switch on the back panel.

3. Turn on the POWER key switch. The display will turn on. The pump current set-point (in % of max) will be displayed in the middle of the screen.

4. Check the temperature status on the bottom left corner of the display. It should show “OK”. If the temperature status shows “Stabilization” for more than 30 seconds or if it shows “Error”, please turn the unit off and contact technical support.

5. Check the emission status of the device on the bottom right corner of the screen. It should show “Off” prior to enabling the amplifier.

6. Make sure the interlock input on the back panel is short-circuited. See Chapter 7 for detailed instructions.

7. Press and release the ENABLE switch to activate the fiber amplifier. There will be a 3 second delay before the fiber amplifier powers up. During this time, the ENABLE indicator will light up and blink.

8. Adjust the pump current set-point to the desired value by pressing the adjustment knob once. The “%” sign blinks in the adjustment mode and it times out after 5 seconds. The knob must be pressed again after the time-out in order to make additional adjustments to the pump current set-point.

9. Ensure that the temperature status still shows “OK” after the pump current has been increased to the desired level. The amplifier is now producing gain and is ready to use.

5.3. Adjusting the Fiber Amplifier Gain
The fiber amplifier gain and output power are controlled by varying the pump current set-point. The system specifications represent the performance at max operating set-point (100%). Each unit is shipped with a test data sheet that shows the amplifier output power at two different input power levels (0 dBm and -20 dBm) as a function of the pump current set-point. The data can be used as a reference to adjust the pump current set-point for a desired gain level.
5.4. Turning the Fiber Amplifier Off

• Disabling the amplifier emission – The amplifier output can be turned off by pressing and releasing the ENABLE switch. The pump diode temperature will be maintained even when the amplifier is disabled. The temperature status should show “OK” after the amplifier has been disabled.
• Power Down – When completely powering down an enabled unit, first press and release the ENABLE switch and then turn off the POWER key switch, which will turn OFF the entire unit. Anytime the unit is turned OFF and then turned back ON, the fiber amplifier will be disabled until the ENABLE switch is pressed. If the amplifier is not being used for an extended period of time, it is recommended to turn off the AC power using the switch located on the back panel of the instrument. Please note that the pump current set-point goes back to 0% after each AC power cycle.

Chapter 6 Remote Operation from Command-Line Interface

The Command Line Interface (CLI) provides the user with a method of controlling the EDFA remotely over the USB interface that is emulating a serial port. A standard terminal program (such as Tera Term) can be used to send commands to the EDFA and receive responses. The following functions are available through the CLI:

• Enabling and disabling the amplifier emission.
• Reading status indicators
• Setting the current set-point value in the ACC operation mode.
• Operating the system in APC or AGC modes at user-defined power or gain values.

The list below shows the list of available commands along with a brief description and syntax: