Fujitsu FIM24721 Series

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Summary

Structure of Micro ICR

Dimensions

Provides physical measurements and tolerances for the Micro ICR package.

Pin functions of Micro ICR

DC pins

Lists and describes the function of each DC pin on the Micro ICR.

RF pins

Lists and describes the function of each RF pin on the Micro ICR.

Control description of Micro ICR

Control terminals

Details the function, pin number, symbol, and operating ranges for control terminals.

Monitor description of Micro ICR

Peak indicator for output

Explains the peak indicator function and its relation to differential output voltage.

Recommended electrical circuit of Micro ICR

Recommended power up sequence of Micro ICR

Recommended power down sequence of Micro ICR

Recommended mounting condition of Micro ICR

Instruction of the Evaluation Board

Introduction

Briefly introduces the purpose and scope of the evaluation board.

Overview

Provides a general description of the evaluation board's features and capabilities.

Monitor Terminals

Lists and describes the monitor terminals available on the evaluation board.

Control Pins

Details the control pins and their corresponding jumper switch settings on the evaluation board.

The Fujitsu Micro Integrated Coherent Receiver (ICR) series, including models FIM24721, FIM24731, FIM24723, and FIM24733, is a sophisticated optical component designed for high-performance coherent optical communication systems. This application note, dated April 23rd, 2018, provides detailed information on its structure, functions, and recommended usage.

Function Description

The Micro ICR is a highly integrated device based on OIF projects, incorporating several key functionalities within a single hermetically sealed package. Its primary function is to receive and process coherent optical signals.

Key functional blocks include:

Eight (8) Photo-detectors: Comprised of four sets of balanced detectors, these convert optical signals into electrical signals.
Four (4) Linear Amplifiers: These provide differential outputs, amplifying the electrical signals from the photo-detectors.
Two (2) Ninety-Degree Hybrid Mixers: These mixers process the input signal, combining it with a local oscillator signal to extract phase and amplitude information.
Polarization Splitter Element: This component separates the input signal into two orthogonal polarizations (X and Y), with each polarization delivered to a hybrid mixer.
Power Splitter: This equally splits the local oscillator power to the two hybrid mixers.
Automatic Gain Control (AGC) and Manual Gain Control (MGC): These features allow for flexible adjustment of the receiver's gain.
User-Settable Independent Output Voltage Swing Adjustment: This enables fine-tuning of the output voltage for each of the four outputs.
Peak Indicators: Provided for each output, these offer visual or electrical indication of signal peaks.
DC Blocker: Included for each output to remove unwanted DC components.
Variable Optical Attenuator (VOA): This allows for adjustment of the optical input power.
Input Signal Power Monitor Photodiode (MPD): This monitors the power of the incoming optical signal.

The device is equipped with various pins for control, monitoring, and power supply.

Important Technical Specifications

The Micro ICR features a compact design with specific dimensions and pin configurations.

Dimensions: The package measures approximately 25mm in length, 18mm in width, and 10.3mm in height (excluding leads). The DC leads are 0.15±0.05mm wide, and the RF leads are 0.3mm wide.
Control Pins:
- MC/AGC (Pin 3): Selects between MGC (0-0.8V) and AGC (2V-Vcc) modes for gain control.
- GA_YI, GA_YQ, GA_XI, GA_XQ (Pins 11, 16, 19, 24): Analog control pins for gain adjustment in MGC mode (0-Vcc).
- OA_YI, OA_YQ, OA_XI, OA_XQ (Pins 12, 15, 20, 23): Analog control pins for output voltage swing adjustment in AGC mode (0.5-2V).
- SD (Pin 32): Shutdown control. 0-0.8V enables shutdown, 2V-Vcc disables shutdown.
- VOA1 (Pin 31): VOA control.
Monitor Pins:
- MPD+ (Pin 4) / MPD- (Pin 5): Monitor Photodiode Cathode/Anode for input signal power monitoring.
- PI-YI, PI-YQ, PI-XI, PI-XQ (Pins 10, 17, 18, 25): Peak indicators for each output. The peak detection voltage varies with differential output voltage, ranging from approximately 0.2V at 100mVpp to 1.9V at 700mVpp.
Power Supply Pins:
- VPD_YIn, VPD_YIp, VPD_YQp, VPD_YQn, VPD_XIn, VPD_XIp, VPD_XQp, VPD_XQn (Pins 6, 7, 8, 9, 26, 27, 28, 29): Photodiode power supply voltages.
- VCC_Y (Pin 13), VCC_X (Pin 22): Amplifier power supply voltages.
RF Pins: The RF outputs are differential and include XIp, XIn, XQp, XQn, YIp, YIn, YQp, YQn, along with multiple GND pins.

Usage Features

The Micro ICR is designed for integration into evaluation boards and larger systems.

Evaluation Board: Fujitsu provides an evaluation board to facilitate testing and characterization of the Micro ICR. This board includes monitor terminals for analog values, jumper switches for terminal control, and GPPO connectors for 32GBaud electrical RF outputs.
Power-Up Sequence: A specific power-up sequence is critical to prevent damage:
1. Prevent electrical surges.
2. Ensure the Micro ICR and evaluation board are disconnected from all external systems.
3. Turn on main switches of DC/AC power supplies/monitors.
4. Set DC power supplies to 0V.
5. Operate DC power supply outputs.
6. Connect the Micro ICR and evaluation board to the evaluation system.
7. Gradually set photodiode power supplies (VPD_XIp, VPD_XIn, VPD_XQp, VPD_XQn, VPD_YIp, VPD_YIn, VPD_YQp, VPD_YQn) from 0V to +5V.
8. Gradually set amplifier power supplies (VCC_X, VCC_Y) from 0V to +3.3V. Crucially, if amplifier power supplies are brought up prior to photodiode power supplies, severe damage to amplifiers and photodiodes will occur. Steps 7 and 8 can be done simultaneously, but the order of voltage application is critical.
9. Turn on optical input.
10. Adjust control terminal voltages (GA_XI, GA_XQ, GA_YI, GA_YQ, OA_XI, OA_XQ, OA_YI, OA_YQ, MC/AGC, SD) for optimal performance.
Power-Down Sequence: An equally important power-down sequence must be followed:
1. Turn off optical input.
2. Gradually set control terminal voltages to 0V.
3. Gradually set amplifier power supplies to 0V. If photodiode power supplies are brought down prior to amplifier power supplies, severe damage will occur. Steps 2 and 3 can be done simultaneously, but the order of voltage removal is critical.
4. Gradually set photodiode power supplies to 0V.
5. Disconnect the receiver and evaluation board from the evaluation system.
6. Stop operating DC/AC power supplies/monitors.
7. Turn off main switches of DC/AC power supplies/monitors.

Maintenance Features

Electro-Static Discharge (ESD) Precautions: The receiver module is highly sensitive to electrical damage. ESD precautions, including the use of ground straps and properly grounded test equipment, are mandatory when handling the device and its AC/DC pins.
DC Power Supply Surge Protection: Photo-diode and TIA DC pins must be connected to a surge suppression filter between all DC power supplies to protect against voltage spikes.
Power-Off During Connection: DC power must be turned off before connecting or disconnecting any electrical cables and optical fiber to prevent damage.
AC Power Noise Protections: All DC power supply grounds and the Device Under Test (DUT) ground must be connected with electrical cables to minimize AC power noise.
Mounting Conditions: The Micro ICR includes precision optics. To prevent degradation or damage from excess load, it must be mounted on a flat surface (flatness < 15µm, surface roughness < 12.5µm) larger than the package bottom area, including flanges. M1.2 screws should be used with a torque of 0.376kgf*cm.
Washing Restrictions: The Micro ICR is not designed to meet aqueous wash requirements. It is explicitly stated that customers should not wash the Micro ICR in water, nor use it near wash bowls, sinks, laundry areas, or in any wet place, as this will cause damage.