3374 Gateway BoulevardFremont, CA 94538, USA
Tel: (510) 490–9930
Fax: (510) 490–9330
URL: http://www.optoplex.com/
Email: sales@optoplex.com

Optoplex

TMCORPORATION

90° Optical Hybrid
To be used for optical coherent detection, including QPSK receiver, Optoplex’s six-port 90° OpticalHybrid mixes the incoming signal with the reference signal to generate four quadratural states in thecomplex-field space. The optical hybrid then delivers the four light signals to two pairs of balanced
detectors. See the block diagram below for the application of 90° Optical Hybrid in a coherent receiver.
Incoming Signal
Polarization
Controller

S+R

90° OpticalHybrid

S− RS+jR

S− jR

Reference

BalancedDetector 1

IBD1

ADC

DSP

TIA
Balanced
Detector 2

IBD2

ADC

Optoplex’s free-space micro-optics-based, passive 90º Optical Hybrid is suitable for coherent signal
demodulation, BPSK or QPSK demodulation. The patent-pending, broadband device accepts the two
optical signals (S & L) and generates four output signals: S+L, S-L, S+jL, S-jL, as shown below. Whenthese signals are detected by two balanced receivers, both the amplitude and the relative phase
information between the input signals can be extracted via differential detection and digital signal
processing. Moreover, in a coherent system, the preservation of the optical phase can be used to costeffectively compensate optical transmission impairments in the electrical domain.

Key Features and Benefits• Purely passive (no need for external

electric power)• Compact size
• Based on free-space bulk-optics design• Polarization diversified version alsoavailable
ReflectiveOptics 1

Unpolarized Beam
Splitter Cube

Reflective
Optics 2Applications• Key component for the optical coherent

detection• QPSK demodulation

Optical Hybrid Standard Product Datasheet
Signal input (S)M1 (S+L)

90° OpticalHybrid

Local oscillator input (L)M2 (S−L)
M3 (S+jL)
M4 (S−jL)

Parameter

Unit

Specification

Wavelength Range (C- or L-Band)nm

1527 ~ 1567

1deg

90 ± 5

S→MidB< 8.5

L→MidB< 8.5

between S→M1 and S→M2dB< 1.2

between S→M3 and S→M4dB< 1.2

between L→M1 and L→M2dB< 1.2

between L→M3 and L→M4dB< 1.2

Optical Return Loss

dB> 27

Optical Path Difference (skew, between M1 and M2
and between M3 and M4)

ps<1

Optical Path Difference (skew, between any othertwo outputs)

mm<2 in fiber length

Operating TemperatureoC

15 ~ 35

Storage TemperatureoC−40 ~ 85mm

30×30×15.5

Fiber Type-SMF-28 with 900 μm loose
tube

Connector Type-

TBD

Phase Difference (between M1, M2 and M3, M4)
1Insertion Loss (withoutconnector)
Insertion Loss
Difference1

Dimension (L×W×H)

2Notes:1. Over the stated spectral and operating temperature ranges and all polarization states.
2. Subject to change, not including collimator sleeves extending from the two adjacent sides by 21 mm.
Optoplex Corporation, located in Fremont, California, is an ISO9001:2000 certified supplier of cutting-edge
photonic components and modules for dynamic wavelength management and signal conditioning. The company
designs, develops, manufactures, and markets innovative fiber-optic products to communications networks, andprovides customized solutions to instrument, defense, spectroscopy and sensing industries. By combining its
proprietary optical design and packaging technology with its state-of-the-art optical coating expertise and facility,
Optoplex supplies DPSK demodulators, DQPSK demodulators, 90° optical hybrids, 2-port tunable optical filters,
3-port reconfigurable optical add/drop multiplexers (ROADMs), optical interleavers, flat-top comb filters, optical
performance monitors (OPMs), and portable spectrometers.